Sciatic nerve forms the tibal nerve and common fibular nerve.
Theses two nerves innervate these muscles.
POSTERIOR THIGH MUSCLE
Muscle 1
Semitendinosus
Proximal Attachment
Ischial tuberosity
Distal Attachment
Medial surface of superior part of tibia
Innervation
Tibial division of sciatic nerve part of tibia (L5, S1, S2)
Function
Extend thigh; flex leg and rotate it medially when knee is flexed; when thigh and leg are flexed, these muscles can extend trunk
Muscle 2
Semimembranosus
Proximal Attachment
Ischial tuberosity
Distal Attachment
Posterior part of medial condyle of tibia; reflected attachment forms oblique popliteal ligament (to lateral femoral condyle)
Innervation
Tibial division of sciatic nerve part of tibia (L5, S1, S2)
Function
Extend thigh; flex leg and rotate it medially when knee is flexed; when thigh and leg are flexed, these muscles can extend trunk
Muscle 3
Biceps femoris
Proximal Attachment
Long head: ischial tuberosity Short head: linea aspera and lateral supracondylar line of femur
Distal Attachment
Lateral side of head of fibula; tendon is split at this site by fibular collateral ligament of knee
Innervation
Long head: tibial division of sciatic nerve (L5, S1, S2) Short head: common fibular division of sciatic nerve (L5, S1, S2)
Funtion
Flexes leg and rotates it laterally when knee is flexed; extends thigh (e.g., accelerating mass during first step of gait).
Tibial Nerve supplies all superficial muscles of posterior compartment of the leg and all these muscles are distally attached to the posterior calcaneus surface by calcaneal tendon.
SUPERFICIAL MUSCLE OF POSTERIOR COMPARTMENT OF THE LEG
Muscle 1
Gastrocnemius
Priximal Attachment
Lateral head: lateral aspect of lateral condyle of femur
Medial head: popliteal surface of femur; superior to medial condyle
Function
Plantarflexes ankle when knee is extended; raises heel during walking; flexes leg at knee joint
Muscle 2
Soleus
Proximal Attachment
Posterior aspect of head and superior quarter of posterior surface of fibula; soleal line and middle third of medial border of tibia; and tendinous arch extending between the bony attachments
Function
Plantarflexes ankle independent of position of knee; steadies leg on foot
Muscle 3
Plantaris
Proximal Attachment
Inferior end of lateral supracondylar line of femur; oblique popliteal ligament
Function
Weakly assists gastrocnemius in plantarflexing ankle
Tibial Nerve also innervates deep muscle of posterior compartment of leg
Muscle 1
Popliteus
Proximal Attachment
Lateral surface of lateral condyle of femur and lateral meniscus
Distal Attachment
Posterior surface of tibia, superior to soleal line
Innervation
Tibial nerve (L4, L5, S1)
Function
Weakly flexes knee and unlocks it by rotating femur 5° on fixed tibia; medially rotates tibia of unplanted limb
Muscle 2
Flexor hallucis longus
Proximal Attachment
Inferior two thirds of posterior surface of fibula; inferior part of interosseous membrane
Distal Attachment
Base of distal phalanx of great toe (hallux)
Innervation
Tibial nerve (S2, S3)
Function
Flexes great toe at all joints; weakly plantarflexes ankle; supports medial longitudinal arch of foot
Muscle 3
Flexor digitorum longus
Proximal Attachment
Medial part of posterior surface of tibia inferior to soleal line; by a broad tendon to fibula
Distal Attachment
Bases of distal phalanges of lateral four digits
Innervation
Tibial nerve (S2, S3)
Function
Flexes lateral four digits; plantarflexes ankle; supports longitudinal arches of foot
Muscle 4
Tibialis posterior
Proximal Attachment
Interosseous membrane; posterior surface of tibia inferior to soleal line; posterior surface of fibula
Distal Attachment
Tuberosity of navicular, cuneiform, cuboid, and sustentaculum tali of calcaneus; bases of 2nd, 3rd, and 4th metatarsals
Innervation
Tibial nerve (L4, L5)
Function
Plantarflexes ankle; inverts foot
Common fibular nerve on theother hand give rise to deep fibular nerve and superficial fibular nerve.
Tibial nerve give rise to medial plantar and lateral plantar nerves.( wow this is too much for muscle to cover on time during pcl!)
FIRST LAYER OF SOLE
Muscle 1
Abductor hallucis
Proximal Attachment
Medial tubercle of tuberosity of calcaneus; flexor retinaculum; plantar aponeurosis
Distal Attachment
Medial side of base of proximal phalanx of 1st digit
Innervation
Medial plantar nerve (S2, S3)
Main Action
Abducts and flexes 1st digit (great toe, hallux)
Muscle 2
Flexor digitorum brevis
Proximal Attachment
Medial tubercle of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa
Distal Attachment
Both sides of middle phalanges of lateral four digits
Innervation
Medial plantar nerve (S2, S3)
Main Action
Flexes lateral four digits
Muscle 3
Abductor digiti minimi
Proximal Attachment
Medial and lateral tubercles of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa
Distal Attachment
Lateral side of base of proximal phalanx of 5th digit
Innervation
Lateral plantar nerve (S2, S3)
Function
Abducts and flexes little toe (5th digit)
SECOND LAYER OF SOLE
Muscle 1
Quadratus plantae
Proximal Attachment
Medial surface and lateral margin of plantar surface of calcaneus
Distal Attachment
Posterolateral margin of tendon of flexor digitorum longus
Innervation
Lateral plantar nerve (S2, S3)
Function
Assists flexor digitorum longus in flexing lateral four digits
Muscle 2
Lumbricals
Proximal Attachment
Tendons of flexor digitorum longus
Distal Attachment
Medial aspect of expansion over lateral four digits
Innervation
Medial one: medial plantar nerve (S2, S3)
Lateral three: lateral plantar nerve (S2, S3)
Function
Flex proximal phalanges, extend middle and distal phalanges of lateral four digits
3rd LAYER OF SOLE
Muscle 1
Flexor hallucis brevis
Proximal Attachment
Plantar surfaces of cuboid and lateral cuneiforms
Distal Attachment
Both sides of base of proximal phalanx of 1st digit
Innervation
Medial plantar nerve (S2, S3)
Function
Flexes proximal phalanx of 1st digit
Muscle 2
Adductor hallucis
Proximal Attachment
Oblique head: bases of metatarsals 2-4
Transverse head: plantar ligaments of metatarsophalangeal (MTP) joints
Distal Attachment
Tendons of both heads attach to lateral side of base of proximal phalanx of 1st digit
Innervation
Deep branch of lateral plantar nerve (S2, S3)
Function
Traditionally said to adduct 1st digit; assists in transverse arch of foot by metatarsals medially
Muscle 3
Flexor digit minimi brevis
Proximal Attachment
Base of 5th metatarsal
Distal Attachment
Base of proximal phalanx of 5th digit
Innervation
Superficial branch of lateral plantar nerve (S2, S3)
Function
Flexes proximal phalanx of 5th digit, thereby assisting with its flexion
FOURTH LAYER OF SOLE
Proximal Attachment
Plantar interossei (three muscles)
Distal Attachment
Bases and medial sides of metatarsals 3-5
Innervation
Medial sides of bases of phalanges of 3rd-5th digits
Function
Lateral plantar nerve (S2, S3)
Muscle 2
Adduct digits (2-4) and flex metatarsophalangeal joints
Proximal Attachment
Dorsal interossei (four muscles)
Distal Attachment
Adjacent sides of metatarsals 1-5
2nd-4th: lateral sides of 2nd-4th digits
Innervation
1st: medial side of proximal phalanx of 2nd digit;
Lateral plantar nerve (S2, S3)
Function
Abduct digits (2-4) and flex metatarsophalangeal joints
DORSUM OF FOOT (alas, last one)
Muscle 1
Extensor digitorum brevis
Proximal Attachment
Calcaneus (floor of tarsal sinus); interosseous talocalcaneal ligament; stem of inferior extensor retinaculum
Distal Attachment
Long extensor tendons of four medial digits (toes 2-4)
Innervation
Deep fibular nerve (L5 or S1, or both)
Function
Aids the extensor digitorum longus in extending the four medial toes at the metatarsophalangeal and interphalangeal joints
Muscle 2
Extensor hallucis brevis
Proximal Attachment
In common with extensor digitorum brevis (above)
Distal Attachment
Dorsal aspect of base of proximal phalanx of great toe (digit 1)
Innervation
Deep fibular nerve (L5 or S1, or both)
Function
Aids the extensor hallucis longus in extending the great toe at the metatarsophalangeal joint
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